romancommander

iTrader: (1)

Hey guys and gals-

I fabbed up an overflow/expansion tank this weekend for my Nova and was curious what the best practice was.

* Currently I have an 18psi cap on my radiator and an 18psi cap on my coolant tank.

* The inlet/outlet on the expansion/overflow is about an inch off of the bottom.

* There is a vent line in the filler neck on the expansion tank.

** I know if I put a "blanking cap" or "cap with no spring" on the radiator, then the external tank functions as an "Expansion tank" with the 18 psi cap on it.

** If I put a put a blanking cap on the external tank, then it functions as an overflow.

My questions are:

1. Is there a problem with leaving a pressurized cap on both tanks?
2. If so, which is better to run, expansion or overflow?

Thanks.

romancommander

iTrader: (1)

Bump for an expert

romancommander

iTrader: (1)

Anybody?

70LS1Nova

I think I can answer question 2 for you. I've run a simple overflow bottle for 10 years now and never had an issue.

romancommander

iTrader: (1)

Yeah I'm leaning toward just doing that. I need to buy a new cap for the overflow bottle.

big hammer

It doesn't really matter. You can even ditch the over flow and it'll be fine.

-TheBandit-

iTrader: (1)

I would use it as just an overflow tank. Unless it's higher than the current radiator and engine there is really no advantage to using it as an expansion tank. If it is higher than radiator and engine, then I would use it as an expansion tank and route the vent line from the cylinder heads up to the expansion tank. That will help burp air from the system. However if you do run it this way, you may have to run a non-pressurized overflow tank in addition to the expansion tank to comply with track rules.

Nice work on all the metal fabrication. I love all the dimpled holes and bead rolls on the cover pieces.